At 5640 m: World's highest observatory put into operation

In the Chilean Atacama Desert, the University of Tokyo Atacama Observatory (TAO), the highest ground-based observatory on earth, has begun operations. The instrument was built on a 5640 m high mountain called Cerro Chajnantor. According to a statement from the University of Tokyo, this was a very special challenge. The milestone that has now been reached was preceded by 26 years of planning and construction, and the first instrument was put into operation in 2009. From its particularly favorable location, the device will now be the only one on Earth to take clear images in the mid-infrared spectrum and investigate emerging exoplanets, for example.

Altitude sickness as a danger

Preparations for the construction began in 1998 and the first ascent to the summit took place in 2002, the university summarizes. A small telescope with a mirror diameter of one meter has been standing there since 2009; the one now in operation is 6.5 meters. The enormous height was not only a particular obstacle during the construction phase, it also poses risks for the researchers on site. For example, there is a risk of them falling ill with altitude sickness, the symptoms of which are particularly bad at night. Ensuring safe working conditions has even been discussed with the Ministry of Health in Chile.

Project manager Yuzuru Yoshii hopes that the instrument, which has now been put into operation, will provide new answers to some of the biggest questions in astronomy. Specifically, he mentions the mysterious dark matter and the very first stars in the universe. In researching these, the instrument benefits from state-of-the-art technology, but above all from the favorable conditions on site. At this altitude, there is only low humidity in the atmosphere, which makes observations in the infrared spectrum more difficult. In future, it will be possible to control the device remotely for the most part.

The University of Tokyo Atacama Observatory is around 400 meters higher than the second highest telescope in the world. It is one of only four instruments that enable observations in the optical spectrum and is located at an altitude of over 4000 meters. At its location, it is also particularly well protected from light pollution; ironically, the light source with the greatest interference factor is the ALMA radio telescope of the European Southern Observatory, which is only 4 km away. Both are in the increasingly sparse locations where light pollution does not exceed the already increased maximum light pollution levels set by the International Astronomical Union.

(mho)